In recent years, there has been a shift towards innovative energy and environmental technologies to moderate climate change, reduce greenhouse gas emissions, reduce air and water pollution, promote economic development, expand energy supply options, increase energy security, decrease dependence on imported oil, and strengthen rural economies.
One of these technologies entails conversion of a carbonaceous feedstock into a product gas which can then be converted into liquid fuels, hydrocarbons and other useful compounds. Carbonaceous materials along with one or more vapor, gaseous, or liquid reactants are introduced into a pressurized reactor where they undergo one or more thermochemical reactions to produce the product gas. Thermochemical processes that convert a carbonaceous material into product gas often also produce solids, such as char, or ash. These highly abrasive and low density solids are elutriated with the pressurized product gas stream. Solids separation devices are often coupled with lock hopper valve arrangements to remove the solids for disposal. The mechanically abrasive solids can cause significant damage or wear on moving parts of process machinery. In a typical lock hopper system operating at reactor pressures, high velocity solid particles scour the valve seats during pressure letdown across the pressure boundary. Over time, the valve seats will degrade, resulting in potentially dangerous gas emissions.
There exists a need for a mechanism and operating protocol to reduce the severity of the pressure drop during solids collection. A need exists for a solids discharge system that is capable of minimizing pressure drop between a reactor at operating pressure and atmospheric pressure so that the solid particles will move slower and with less momentum, and therefore less force, with which to abrade the valve seats, thereby significantly prolonging the life of the equipment and ensuring operational safety.